Urea is commonly used as a fertiliser, supplying nitrogen to plants. Biuret is a phytotoxin (a material that is toxic to plants) and is formed as an impurity during the production of urea fertilisers. Biuret interferes with nitrogen metabolism and protein synthesis in plants.
It is desirable to reduce the amount of biuret in fertilisers. US 2009 019906 discloses a process for producing urea fertilisers wherein a centrigual pump is employed. The use of the pump allows for the use of shorter pipelines, thereby decreasing the residence time and reducing biuret formation during urea synthesis.
The present inventors have sought to prepare a urea fertiliser having reduced biuret concentration.